ops: run 'tsc' on CI (#51)

Author: jbottigliero

.github/workflows/ci.yml

@@ -16,4 +16,5 @@ jobs:
           node-version: lts/hydrogen
           cache: "npm"
       - run: npm install
-      - run: npm run lint
+      - run: npm run lint
+      - run: npx tsc --noEmit